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src/share/vm/memory/gcLocker.cpp@f95d63e2154a (annotated)

src/share/vm/memory/gcLocker.cpp

Tue, 23 Nov 2010 13:22:55 -0800

author

stefank

date

Tue, 23 Nov 2010 13:22:55 -0800

changeset 2314

f95d63e2154a

parent 1907

c18cbe5936b8

child 3494

1a2723f7ad8e

permissions

-rw-r--r--

6989984: Use standard include model for Hospot
Summary: Replaced MakeDeps and the includeDB files with more standardized solutions.
Reviewed-by: coleenp, kvn, kamg

duke@435	1	/*
stefank@2314	2	* Copyright (c) 1997, 2010, Oracle and/or its affiliates. All rights reserved.
duke@435	3	* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
duke@435	4	*
duke@435	5	* This code is free software; you can redistribute it and/or modify it
duke@435	6	* under the terms of the GNU General Public License version 2 only, as
duke@435	7	* published by the Free Software Foundation.
duke@435	8	*
duke@435	9	* This code is distributed in the hope that it will be useful, but WITHOUT
duke@435	10	* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
duke@435	11	* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
duke@435	12	* version 2 for more details (a copy is included in the LICENSE file that
duke@435	13	* accompanied this code).
duke@435	14	*
duke@435	15	* You should have received a copy of the GNU General Public License version
duke@435	16	* 2 along with this work; if not, write to the Free Software Foundation,
duke@435	17	* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
duke@435	18	*
trims@1907	19	* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
trims@1907	20	* or visit www.oracle.com if you need additional information or have any
trims@1907	21	* questions.
duke@435	22	*
duke@435	23	*/
duke@435	24
stefank@2314	25	#include "precompiled.hpp"
stefank@2314	26	#include "memory/gcLocker.inline.hpp"
stefank@2314	27	#include "memory/resourceArea.hpp"
stefank@2314	28	#include "memory/sharedHeap.hpp"
duke@435	29
duke@435	30	volatile jint GC_locker::_jni_lock_count = 0;
duke@435	31	volatile jint GC_locker::_lock_count = 0;
duke@435	32	volatile bool GC_locker::_needs_gc = false;
duke@435	33	volatile bool GC_locker::_doing_gc = false;
duke@435	34
duke@435	35	void GC_locker::stall_until_clear() {
duke@435	36	assert(!JavaThread::current()->in_critical(), "Would deadlock");
apetrusenko@574	37	if (PrintJNIGCStalls && PrintGCDetails) {
apetrusenko@574	38	ResourceMark rm; // JavaThread::name() allocates to convert to UTF8
apetrusenko@574	39	gclog_or_tty->print_cr(
apetrusenko@574	40	"Allocation failed. Thread \"%s\" is stalled by JNI critical section.",
apetrusenko@574	41	JavaThread::current()->name());
apetrusenko@574	42	}
duke@435	43	MutexLocker ml(JNICritical_lock);
duke@435	44	// Wait for _needs_gc to be cleared
duke@435	45	while (GC_locker::needs_gc()) {
duke@435	46	JNICritical_lock->wait();
duke@435	47	}
duke@435	48	}
duke@435	49
duke@435	50	void GC_locker::jni_lock_slow() {
duke@435	51	MutexLocker mu(JNICritical_lock);
duke@435	52	// Block entering threads if we know at least one thread is in a
duke@435	53	// JNI critical region and we need a GC.
duke@435	54	// We check that at least one thread is in a critical region before
duke@435	55	// blocking because blocked threads are woken up by a thread exiting
duke@435	56	// a JNI critical region.
duke@435	57	while ((is_jni_active() && needs_gc()) || _doing_gc) {
duke@435	58	JNICritical_lock->wait();
duke@435	59	}
duke@435	60	jni_lock();
duke@435	61	}
duke@435	62
duke@435	63	void GC_locker::jni_unlock_slow() {
duke@435	64	MutexLocker mu(JNICritical_lock);
duke@435	65	jni_unlock();
duke@435	66	if (needs_gc() && !is_jni_active()) {
duke@435	67	// We're the last thread out. Cause a GC to occur.
duke@435	68	// GC will also check is_active, so this check is not
duke@435	69	// strictly needed. It's added here to make it clear that
duke@435	70	// the GC will NOT be performed if any other caller
duke@435	71	// of GC_locker::lock() still needs GC locked.
duke@435	72	if (!is_active()) {
duke@435	73	_doing_gc = true;
duke@435	74	{
duke@435	75	// Must give up the lock while at a safepoint
duke@435	76	MutexUnlocker munlock(JNICritical_lock);
duke@435	77	Universe::heap()->collect(GCCause::_gc_locker);
duke@435	78	}
duke@435	79	_doing_gc = false;
duke@435	80	}
duke@435	81	clear_needs_gc();
duke@435	82	JNICritical_lock->notify_all();
duke@435	83	}
duke@435	84	}
duke@435	85
duke@435	86	// Implementation of No_GC_Verifier
duke@435	87
duke@435	88	#ifdef ASSERT
duke@435	89
duke@435	90	No_GC_Verifier::No_GC_Verifier(bool verifygc) {
duke@435	91	_verifygc = verifygc;
duke@435	92	if (_verifygc) {
duke@435	93	CollectedHeap* h = Universe::heap();
duke@435	94	assert(!h->is_gc_active(), "GC active during No_GC_Verifier");
duke@435	95	_old_invocations = h->total_collections();
duke@435	96	}
duke@435	97	}
duke@435	98
duke@435	99
duke@435	100	No_GC_Verifier::~No_GC_Verifier() {
duke@435	101	if (_verifygc) {
duke@435	102	CollectedHeap* h = Universe::heap();
duke@435	103	assert(!h->is_gc_active(), "GC active during No_GC_Verifier");
duke@435	104	if (_old_invocations != h->total_collections()) {
duke@435	105	fatal("collection in a No_GC_Verifier secured function");
duke@435	106	}
duke@435	107	}
duke@435	108	}
duke@435	109
duke@435	110	Pause_No_GC_Verifier::Pause_No_GC_Verifier(No_GC_Verifier * ngcv) {
duke@435	111	_ngcv = ngcv;
duke@435	112	if (_ngcv->_verifygc) {
duke@435	113	// if we were verifying, then make sure that nothing is
duke@435	114	// wrong before we "pause" verification
duke@435	115	CollectedHeap* h = Universe::heap();
duke@435	116	assert(!h->is_gc_active(), "GC active during No_GC_Verifier");
duke@435	117	if (_ngcv->_old_invocations != h->total_collections()) {
duke@435	118	fatal("collection in a No_GC_Verifier secured function");
duke@435	119	}
duke@435	120	}
duke@435	121	}
duke@435	122
duke@435	123
duke@435	124	Pause_No_GC_Verifier::~Pause_No_GC_Verifier() {
duke@435	125	if (_ngcv->_verifygc) {
duke@435	126	// if we were verifying before, then reenable verification
duke@435	127	CollectedHeap* h = Universe::heap();
duke@435	128	assert(!h->is_gc_active(), "GC active during No_GC_Verifier");
duke@435	129	_ngcv->_old_invocations = h->total_collections();
duke@435	130	}
duke@435	131	}
duke@435	132
duke@435	133
duke@435	134	// JRT_LEAF rules:
duke@435	135	// A JRT_LEAF method may not interfere with safepointing by
duke@435	136	// 1) acquiring or blocking on a Mutex or JavaLock - checked
duke@435	137	// 2) allocating heap memory - checked
duke@435	138	// 3) executing a VM operation - checked
duke@435	139	// 4) executing a system call (including malloc) that could block or grab a lock
duke@435	140	// 5) invoking GC
duke@435	141	// 6) reaching a safepoint
duke@435	142	// 7) running too long
duke@435	143	// Nor may any method it calls.
duke@435	144	JRT_Leaf_Verifier::JRT_Leaf_Verifier()
duke@435	145	: No_Safepoint_Verifier(true, JRT_Leaf_Verifier::should_verify_GC())
duke@435	146	{
duke@435	147	}
duke@435	148
duke@435	149	JRT_Leaf_Verifier::~JRT_Leaf_Verifier()
duke@435	150	{
duke@435	151	}
duke@435	152
duke@435	153	bool JRT_Leaf_Verifier::should_verify_GC() {
duke@435	154	switch (JavaThread::current()->thread_state()) {
duke@435	155	case _thread_in_Java:
duke@435	156	// is in a leaf routine, there must be no safepoint.
duke@435	157	return true;
duke@435	158	case _thread_in_native:
duke@435	159	// A native thread is not subject to safepoints.
duke@435	160	// Even while it is in a leaf routine, GC is ok
duke@435	161	return false;
duke@435	162	default:
duke@435	163	// Leaf routines cannot be called from other contexts.
duke@435	164	ShouldNotReachHere();
duke@435	165	return false;
duke@435	166	}
duke@435	167	}
duke@435	168	#endif